var f = function (a) { return document.getElementById(a); }
var onbtn=f("isbtn");
//if (!IsPC()) {
onbtn.onclick=function(){
    f("isnav").style.display="block";
    stopBubble(event);
    document.onclick=function(){
        f('isnav').style.display='none';　
      }
}
//}

function stopBubble(eve){  
    if(eve && eve.stopPropagation){
      eve.stopPropagation();  
    }else{
      window.event.cancelBubble=true; //IE
    }
  }

function IsPC() {
  var userAgentInfo = navigator.userAgent;
  var Agents = ["Android", "iPhone",
    "SymbianOS", "Windows Phone",
    "iPad", "iPod"];
  var flag = true;
  for (var v = 0; v < Agents.length; v++) {
    if (userAgentInfo.indexOf(Agents[v]) > 0) {
      flag = false;
      break;
    }
  }
  return flag;
}